/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2011 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sinosoft.monitor.org.objectweb.asm.tree.analysis;

import java.util.List;

import com.sinosoft.monitor.org.objectweb.asm.Type;
import com.sinosoft.monitor.org.objectweb.asm.tree.AbstractInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.FieldInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.InvokeDynamicInsnNode;
import com.sinosoft.monitor.org.objectweb.asm.tree.MethodInsnNode;

/**
 * An extended {@link BasicInterpreter} that checks that bytecode instructions
 * are correctly used.
 *
 * @author Eric Bruneton
 * @author Bing Ran
 */
public class BasicVerifier extends BasicInterpreter {

	public BasicVerifier() {
		super(ASM4);
	}

	protected BasicVerifier(final int api) {
		super(api);
	}

	@Override
	public BasicValue copyOperation(final AbstractInsnNode insn,
	                                final BasicValue value) throws AnalyzerException {
		Value expected;
		switch (insn.getOpcode()) {
			case ILOAD:
			case ISTORE:
				expected = BasicValue.INT_VALUE;
				break;
			case FLOAD:
			case FSTORE:
				expected = BasicValue.FLOAT_VALUE;
				break;
			case LLOAD:
			case LSTORE:
				expected = BasicValue.LONG_VALUE;
				break;
			case DLOAD:
			case DSTORE:
				expected = BasicValue.DOUBLE_VALUE;
				break;
			case ALOAD:
				if (!value.isReference()) {
					throw new AnalyzerException(insn, null, "an object reference",
							value);
				}
				return value;
			case ASTORE:
				if (!value.isReference()
						&& !BasicValue.RETURNADDRESS_VALUE.equals(value)) {
					throw new AnalyzerException(insn, null,
							"an object reference or a return address", value);
				}
				return value;
			default:
				return value;
		}
		if (!expected.equals(value)) {
			throw new AnalyzerException(insn, null, expected, value);
		}
		return value;
	}

	@Override
	public BasicValue unaryOperation(final AbstractInsnNode insn,
	                                 final BasicValue value) throws AnalyzerException {
		BasicValue expected;
		switch (insn.getOpcode()) {
			case INEG:
			case IINC:
			case I2F:
			case I2L:
			case I2D:
			case I2B:
			case I2C:
			case I2S:
			case IFEQ:
			case IFNE:
			case IFLT:
			case IFGE:
			case IFGT:
			case IFLE:
			case TABLESWITCH:
			case LOOKUPSWITCH:
			case IRETURN:
			case NEWARRAY:
			case ANEWARRAY:
				expected = BasicValue.INT_VALUE;
				break;
			case FNEG:
			case F2I:
			case F2L:
			case F2D:
			case FRETURN:
				expected = BasicValue.FLOAT_VALUE;
				break;
			case LNEG:
			case L2I:
			case L2F:
			case L2D:
			case LRETURN:
				expected = BasicValue.LONG_VALUE;
				break;
			case DNEG:
			case D2I:
			case D2F:
			case D2L:
			case DRETURN:
				expected = BasicValue.DOUBLE_VALUE;
				break;
			case GETFIELD:
				expected = newValue(Type
						.getObjectType(((FieldInsnNode) insn).owner));
				break;
			case CHECKCAST:
				if (!value.isReference()) {
					throw new AnalyzerException(insn, null, "an object reference",
							value);
				}
				return super.unaryOperation(insn, value);
			case ARRAYLENGTH:
				if (!isArrayValue(value)) {
					throw new AnalyzerException(insn, null, "an array reference",
							value);
				}
				return super.unaryOperation(insn, value);
			case ARETURN:
			case ATHROW:
			case INSTANCEOF:
			case MONITORENTER:
			case MONITOREXIT:
			case IFNULL:
			case IFNONNULL:
				if (!value.isReference()) {
					throw new AnalyzerException(insn, null, "an object reference",
							value);
				}
				return super.unaryOperation(insn, value);
			case PUTSTATIC:
				expected = newValue(Type.getType(((FieldInsnNode) insn).desc));
				break;
			default:
				throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value, expected)) {
			throw new AnalyzerException(insn, null, expected, value);
		}
		return super.unaryOperation(insn, value);
	}

	@Override
	public BasicValue binaryOperation(final AbstractInsnNode insn,
	                                  final BasicValue value1, final BasicValue value2)
			throws AnalyzerException {
		BasicValue expected1;
		BasicValue expected2;
		switch (insn.getOpcode()) {
			case IALOAD:
				expected1 = newValue(Type.getType("[I"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case BALOAD:
				if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
					expected1 = newValue(Type.getType("[Z"));
				} else {
					expected1 = newValue(Type.getType("[B"));
				}
				expected2 = BasicValue.INT_VALUE;
				break;
			case CALOAD:
				expected1 = newValue(Type.getType("[C"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case SALOAD:
				expected1 = newValue(Type.getType("[S"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case LALOAD:
				expected1 = newValue(Type.getType("[J"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case FALOAD:
				expected1 = newValue(Type.getType("[F"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case DALOAD:
				expected1 = newValue(Type.getType("[D"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case AALOAD:
				expected1 = newValue(Type.getType("[Ljava/lang/Object;"));
				expected2 = BasicValue.INT_VALUE;
				break;
			case IADD:
			case ISUB:
			case IMUL:
			case IDIV:
			case IREM:
			case ISHL:
			case ISHR:
			case IUSHR:
			case IAND:
			case IOR:
			case IXOR:
			case IF_ICMPEQ:
			case IF_ICMPNE:
			case IF_ICMPLT:
			case IF_ICMPGE:
			case IF_ICMPGT:
			case IF_ICMPLE:
				expected1 = BasicValue.INT_VALUE;
				expected2 = BasicValue.INT_VALUE;
				break;
			case FADD:
			case FSUB:
			case FMUL:
			case FDIV:
			case FREM:
			case FCMPL:
			case FCMPG:
				expected1 = BasicValue.FLOAT_VALUE;
				expected2 = BasicValue.FLOAT_VALUE;
				break;
			case LADD:
			case LSUB:
			case LMUL:
			case LDIV:
			case LREM:
			case LAND:
			case LOR:
			case LXOR:
			case LCMP:
				expected1 = BasicValue.LONG_VALUE;
				expected2 = BasicValue.LONG_VALUE;
				break;
			case LSHL:
			case LSHR:
			case LUSHR:
				expected1 = BasicValue.LONG_VALUE;
				expected2 = BasicValue.INT_VALUE;
				break;
			case DADD:
			case DSUB:
			case DMUL:
			case DDIV:
			case DREM:
			case DCMPL:
			case DCMPG:
				expected1 = BasicValue.DOUBLE_VALUE;
				expected2 = BasicValue.DOUBLE_VALUE;
				break;
			case IF_ACMPEQ:
			case IF_ACMPNE:
				expected1 = BasicValue.REFERENCE_VALUE;
				expected2 = BasicValue.REFERENCE_VALUE;
				break;
			case PUTFIELD:
				FieldInsnNode fin = (FieldInsnNode) insn;
				expected1 = newValue(Type.getObjectType(fin.owner));
				expected2 = newValue(Type.getType(fin.desc));
				break;
			default:
				throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value1, expected1)) {
			throw new AnalyzerException(insn, "First argument", expected1,
					value1);
		} else if (!isSubTypeOf(value2, expected2)) {
			throw new AnalyzerException(insn, "Second argument", expected2,
					value2);
		}
		if (insn.getOpcode() == AALOAD) {
			return getElementValue(value1);
		} else {
			return super.binaryOperation(insn, value1, value2);
		}
	}

	@Override
	public BasicValue ternaryOperation(final AbstractInsnNode insn,
	                                   final BasicValue value1, final BasicValue value2,
	                                   final BasicValue value3) throws AnalyzerException {
		BasicValue expected1;
		BasicValue expected3;
		switch (insn.getOpcode()) {
			case IASTORE:
				expected1 = newValue(Type.getType("[I"));
				expected3 = BasicValue.INT_VALUE;
				break;
			case BASTORE:
				if (isSubTypeOf(value1, newValue(Type.getType("[Z")))) {
					expected1 = newValue(Type.getType("[Z"));
				} else {
					expected1 = newValue(Type.getType("[B"));
				}
				expected3 = BasicValue.INT_VALUE;
				break;
			case CASTORE:
				expected1 = newValue(Type.getType("[C"));
				expected3 = BasicValue.INT_VALUE;
				break;
			case SASTORE:
				expected1 = newValue(Type.getType("[S"));
				expected3 = BasicValue.INT_VALUE;
				break;
			case LASTORE:
				expected1 = newValue(Type.getType("[J"));
				expected3 = BasicValue.LONG_VALUE;
				break;
			case FASTORE:
				expected1 = newValue(Type.getType("[F"));
				expected3 = BasicValue.FLOAT_VALUE;
				break;
			case DASTORE:
				expected1 = newValue(Type.getType("[D"));
				expected3 = BasicValue.DOUBLE_VALUE;
				break;
			case AASTORE:
				expected1 = value1;
				expected3 = BasicValue.REFERENCE_VALUE;
				break;
			default:
				throw new Error("Internal error.");
		}
		if (!isSubTypeOf(value1, expected1)) {
			throw new AnalyzerException(insn, "First argument", "a "
					+ expected1 + " array reference", value1);
		} else if (!BasicValue.INT_VALUE.equals(value2)) {
			throw new AnalyzerException(insn, "Second argument",
					BasicValue.INT_VALUE, value2);
		} else if (!isSubTypeOf(value3, expected3)) {
			throw new AnalyzerException(insn, "Third argument", expected3,
					value3);
		}
		return null;
	}

	@Override
	public BasicValue naryOperation(final AbstractInsnNode insn,
	                                final List<? extends BasicValue> values) throws AnalyzerException {
		int opcode = insn.getOpcode();
		if (opcode == MULTIANEWARRAY) {
			for (int i = 0; i < values.size(); ++i) {
				if (!BasicValue.INT_VALUE.equals(values.get(i))) {
					throw new AnalyzerException(insn, null,
							BasicValue.INT_VALUE, values.get(i));
				}
			}
		} else {
			int i = 0;
			int j = 0;
			if (opcode != INVOKESTATIC && opcode != INVOKEDYNAMIC) {
				Type owner = Type.getObjectType(((MethodInsnNode) insn).owner);
				if (!isSubTypeOf(values.get(i++), newValue(owner))) {
					throw new AnalyzerException(insn, "Method owner",
							newValue(owner), values.get(0));
				}
			}
			String desc = (opcode == INVOKEDYNAMIC) ? ((InvokeDynamicInsnNode) insn).desc
					: ((MethodInsnNode) insn).desc;
			Type[] args = Type.getArgumentTypes(desc);
			while (i < values.size()) {
				BasicValue expected = newValue(args[j++]);
				BasicValue encountered = values.get(i++);
				if (!isSubTypeOf(encountered, expected)) {
					throw new AnalyzerException(insn, "Argument " + j,
							expected, encountered);
				}
			}
		}
		return super.naryOperation(insn, values);
	}

	@Override
	public void returnOperation(final AbstractInsnNode insn,
	                            final BasicValue value, final BasicValue expected)
			throws AnalyzerException {
		if (!isSubTypeOf(value, expected)) {
			throw new AnalyzerException(insn, "Incompatible return type",
					expected, value);
		}
	}

	protected boolean isArrayValue(final BasicValue value) {
		return value.isReference();
	}

	protected BasicValue getElementValue(final BasicValue objectArrayValue)
			throws AnalyzerException {
		return BasicValue.REFERENCE_VALUE;
	}

	protected boolean isSubTypeOf(final BasicValue value,
	                              final BasicValue expected) {
		return value.equals(expected);
	}
}
